Outstanding research achievements: Soil Science

Research was focused on characterizing soil and water resources, monitoring secondary- and micro-nutrient deficiency, and fine-tuning fertilizer and water management practices for conserving resources and enhancing crop productivity.

Resource characterization

• Coarse fraction in Punjab soils is dominated by quartz and followed by feldspars, micas and calcite; while finer fraction is dominated by illite and followed by smectite, vermiculite, chlorite, and kaolinite.
• Soil pockets rich in selenium exist in north-eastern part and need careful management.
• Arsenic concentration of aquifer in south-western part was higher than in the kandi and central region of the state.
• GIS- based soil fertility and water quality maps of the state have been finalized.
• District- level survey for micro-nutrient analysis of soils showed that 22, 11, 11 and 2 percent samples were deficient in Zn, Mn, Fe and Cu.
• High amount of uranium in groundwater of south-west Punjab is not associated with use of phosphatic fertilizers.

Soil fertility and plant nutrition

• Nitrogen application to cereals like rice, maize and wheat using leaf color chart (LCC) saved 15-20 % fertilizers without any yield loss.
• Neem-coated urea was as much efficient as ordinary urea.
• Phosphorus should be applied to rabi crops and omitted in the following kharif crops.
• Sulphated P fertilizers are effective source of phosphorus and sulphur in maize and raya.
• Incorporating rice residues 15-20 days prior to sowing wheat had no adverse effects on wheat yields.
• In manganese- deficient soils, 3- 4 foliar application of 0.5 % MnSO₄ to wheat at 7-10 d interval beginning prior to first irrigation is helpful in ameliorating Mn deficiency.
• Green manuring with Sesbenia controls iron deficiency in rice.
• Long-term use of fertilizers and FYM in maize-wheat resulted in build-up of soil organic carbon and available nutrients suggesting that P application could be reduced.
• FYM and green manure (Sesbenia and Sunhemp) saved 40-60 kg N ha^-1 in rice.
• Poultry manure @ 5 t ha^-1 saved 80 kg N ha^-1 in rice, and 30 kg N + 30 kg P₂O₅ ha^-1 in following wheat.
• Application of biogas slurry at 12 t ha^-1 substituted for 80 kg fertilizer N ha^-1 in rice and significantly improved the yield of following wheat crop.
• Application of sewage sludge (5- 10 t ha^-1) can save 30- 60 kg ha^-1 N in rice.
• Application of bagasse ash and rice husk ash (10- 20 t ha^-1) increased grain yield of rice and wheat and enhanced available soil P.
• Foliar application of 0.5 % ZnSO₄ and FeSO₄ enhanced their concentration in rice grain.
• Application of sewage sludge (5 t ha^-1) saved 30 kg ha^-1 N in wheat, and accumulation of toxic elements in soil (Pb and Cr) was within safe limits.
• Soil application of boron @ 1kg ha^-1 caused 15 % increase in bulb yield of onion in a boron deficient soil (< 0.5 mg kg^-1 soil)
• · Incorporating rice residues before sowing wheat caused a saving of 30 kg fertilizer N ha^-1 in succeeding rice.
• Soil organic carbon stock in 0-0.15 m layer was 30, 21, 17 and 3.6 t ha^-1 in a grass, forest, agricultural and eroded land in a watershed in lower Shivaliks.

Water management

• Water economizing irrigation schedules have been developed for wheat, sugarcane and other rabi crops based on a simple evaporative demand- based approach.
• Irrigation scheduling to rice based on 2-d drainage saved 30 % water compared to continuous submergence without any adverse effects on crop yield.
• Shifting rice transplanting from mid- May to mid-June caused substantial saving in evapo-transpiration (ET) and irrigation without much loss in crop yields.
• Transplanting sunflower in early February increased yield and saved irrigation water than direct-seeded crop.
• Bed / ridge planting of rice is helpful in saving irrigation and fertilizer N.
• Plot size of 250 m²in coarse-textured soils and 500 m² in fine-textured soils enhance irrigation efficiency.
• Straw mulching in maize, sugarcane, soybean, chilies and potato enhanced economic yield and saved irrigation and fertilizer N.
• Narrow bed planting of potato improved yield and saved irrigation and fertilizer N.
• Puddling twice in medium textured soils was optimum for reducing percolation losses in rice with no adverse effects on following wheat.
• Deep tillage responses of maize, sunflower and soybean were more in low retentive loamy sand soil.
• Amending sodic waters with gypsum and FYM caused improvements in sugarcane yield.
• In calcareous soils with more than 2 % CaCO3, use of organic like FYM, green manure or wheat straw reduces harmful effects of sodic water irrigations.
• Alternating canal (CW) and sodic water (SW) irrigation (2CW/SW or SW/2CW) gave as much seed- cotton yield as with CW alone.